164 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			164 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*-
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 * Copyright (c) 2006,2008 Joseph Koshy
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <sys/cdefs.h>
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#include <sys/types.h>
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#include <sys/errno.h>
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#if 0
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#include <sys/mman.h>
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#endif
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#include <sys/stat.h>
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#include <ar.h>
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#include <ctype.h>
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#include <errno.h>
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#include <libelf.h>
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#include <unistd.h>
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#include "_libelf.h"
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LIBELF_VCSID("$Id$");
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static Elf *
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_libelf_open_object(int fd, Elf_Cmd c)
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{
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	Elf *e;
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	void *m;
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	struct stat sb;
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	/*
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	 * 'Raw' files are always mapped with 'PROT_READ'.  At
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	 * elf_update(3) time for files opened with ELF_C_RDWR the
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	 * mapping is unmapped, file data is written to using write(2)
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	 * and then the raw data is immediately mapped back in.
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	 */
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	if (fstat(fd, &sb) < 0) {
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		LIBELF_SET_ERROR(IO, errno);
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		return (NULL);
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	}
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	m = NULL;
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	if ((m = mmap(NULL, (size_t) sb.st_size, PROT_READ, MAP_PRIVATE, fd,
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	    (off_t) 0)) == MAP_FAILED) {
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		LIBELF_SET_ERROR(IO, errno);
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		return (NULL);
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	}
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	if ((e = elf_memory(m, (size_t) sb.st_size)) == NULL) {
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		(void) munmap(m, (size_t) sb.st_size);
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		return (NULL);
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	}
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	e->e_flags |= LIBELF_F_MMAP;
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	e->e_fd = fd;
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	e->e_cmd = c;
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	if (c == ELF_C_RDWR && e->e_kind == ELF_K_AR) {
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		(void) elf_end(e);
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		LIBELF_SET_ERROR(ARGUMENT, 0);
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		return (NULL);
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	}
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	return (e);
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}
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Elf *
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elf_begin(int fd, Elf_Cmd c, Elf *a)
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{
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	Elf *e;
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	e = NULL;
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	if (LIBELF_PRIVATE(version) == EV_NONE) {
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		LIBELF_SET_ERROR(SEQUENCE, 0);
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		return (NULL);
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	}
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	switch (c) {
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	case ELF_C_NULL:
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		return (NULL);
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	case ELF_C_WRITE:
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		if (a != NULL) { /* not allowed for ar(1) archives. */
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			LIBELF_SET_ERROR(ARGUMENT, 0);
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			return (NULL);
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		}
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		/*
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		 * Check writeability of `fd' immediately and fail if
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		 * not writeable.
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		 */
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		if (ftruncate(fd, (off_t) 0) < 0) {
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			LIBELF_SET_ERROR(IO, errno);
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			return (NULL);
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		}
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		if ((e = _libelf_allocate_elf()) != NULL) {
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			_libelf_init_elf(e, ELF_K_ELF);
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			e->e_byteorder = LIBELF_PRIVATE(byteorder);
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			e->e_fd = fd;
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			e->e_cmd = c;
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		}
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		return (e);
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	case ELF_C_RDWR:
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		if (a != NULL) { /* not allowed for ar(1) archives. */
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			LIBELF_SET_ERROR(ARGUMENT, 0);
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			return (NULL);
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		}
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		/*FALLTHROUGH*/
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	case ELF_C_READ:
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		/*
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		 * Descriptor `a' could be for a regular ELF file, or
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		 * for an ar(1) archive.  If descriptor `a' was opened
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		 * using a valid file descriptor, we need to check if
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		 * the passed in `fd' value matches the original one.
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		 */
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		if (a &&
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		    ((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) {
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			LIBELF_SET_ERROR(ARGUMENT, 0);
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			return (NULL);
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		}
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		break;
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	default:
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		LIBELF_SET_ERROR(ARGUMENT, 0);
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		return (NULL);
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	}
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	if (a == NULL)
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		e = _libelf_open_object(fd, c);
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	else if (a->e_kind == ELF_K_AR)
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		e = _libelf_ar_open_member(a->e_fd, c, a);
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	else
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		(e = a)->e_activations++;
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	return (e);
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}
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